clixon/example/main/example_backend_nacm.c

/*
 *
  ***** BEGIN LICENSE BLOCK *****
 
  Copyright (C) 2017-2019 Olof Hagsand
  Copyright (C) 2020 Olof Hagsand and Rubicon Communications, LLC(Netgate)

  This file is part of CLIXON.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

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  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
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  in which case the provisions of the GPL are applicable instead
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 * 
 * Secondary backend for testing more than one backend plugin, with the following 
 * features:
 * - nacm
 * - transaction test
 *  -t  enable transaction logging (call syslog for every transaction)
 *  -v <xpath> Failing validate and commit if <xpath> is present (synthetic error)
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/syslog.h>

/* clicon */
#include <cligen/cligen.h>

/* Clicon library functions. */
#include <clixon/clixon.h>

/* These include signatures for plugin and transaction callbacks. */
#include <clixon/clixon_backend.h> 

/* Command line options to be passed to getopt(3) */
#define BACKEND_NACM_OPTS "tv:"

/*! Variable to control transaction logging (for debug)
 * If set, call syslog for every transaction callback
 * Start backend with -- -t
 */
static int _transaction_log = 0;

/*! Variable to control transaction logging (for debug)
 * If set, call syslog for every transaction callback 
 * Start backend with -- -v <xpath>
 */
static char *_validate_fail_xpath = NULL;
static int   _validate_fail_toggle = 0; /* fail at validate and commit */

int
nacm_begin(clicon_handle    h, 
	   transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    return 0;
}
/*! This is called on validate (and commit). Check validity of candidate
 */
int
nacm_validate(clicon_handle    h, 
	      transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    if (_validate_fail_xpath){
	if (_validate_fail_toggle==0 &&
	    xpath_first(transaction_target(td), NULL, "%s", _validate_fail_xpath)){
	    _validate_fail_toggle = 1; /* toggle if triggered */
	    clicon_err(OE_XML, 0, "User error");
	    return -1; /* induce fail */
	}
    }
    return 0;
}

int
nacm_complete(clicon_handle    h, 
	      transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    return 0;
}

/*! This is called on commit. Identify modifications and adjust machine state
 */
int
nacm_commit(clicon_handle    h, 
	    transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    if (_validate_fail_xpath){
	if (_validate_fail_toggle==1 &&
	    xpath_first(transaction_target(td), NULL, "%s", _validate_fail_xpath)){
	    _validate_fail_toggle = 0; /* toggle if triggered */
	    clicon_err(OE_XML, 0, "User error");
	    return -1; /* induce fail */
	}
    }
    return 0;
}

int
nacm_commit_done(clicon_handle    h, 
		 transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    return 0;
}

int
nacm_revert(clicon_handle    h, 
	    transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    return 0;
}

int
nacm_end(clicon_handle    h, 
	 transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
    return 0;
}

int
nacm_abort(clicon_handle    h, 
	   transaction_data td)
{
    if (_transaction_log)
	transaction_log(h, td, LOG_NOTICE,  __FUNCTION__);
    return 0;
}

/*! Called to get NACM state data
 * @param[in]    h      Clicon handle
 * @param[in]    nsc    External XML namespace context, or NULL
 * @param[in]    xpath  String with XPATH syntax. or NULL for all
 * @param[in]    xtop   XML tree, <config/> on entry. 
 * @retval       0      OK
 * @retval      -1      Error
 * @see xmldb_get
 * @note this example code returns a static statedata used in testing. 
 * Real code would poll state
 */
int 
nacm_statedata(clicon_handle h, 
	       cvec         *nsc,
	       char         *xpath,
	       cxobj        *xstate)
{
    int     retval = -1;
    cxobj **xvec = NULL;

    /* Example of (static) statedata, real code would poll state */
    if (clixon_xml_parse_string("<nacm xmlns=\"urn:ietf:params:xml:ns:yang:ietf-netconf-acm\">"
				"<denied-data-writes>0</denied-data-writes>"
				"<denied-operations>0</denied-operations>"
				"<denied-notifications>0</denied-notifications>"
				"</nacm>", YB_NONE, NULL, &xstate, NULL) < 0)
	goto done;
    retval = 0;
 done:
    if (xvec)
	free(xvec);
    return retval;
}

clixon_plugin_api *clixon_plugin_init(clicon_handle h);

static clixon_plugin_api api = {
    "nacm",             /* name */           /*--- Common fields.  ---*/
    clixon_plugin_init, /* init */
    NULL,               /* start */
    NULL,               /* exit */
    .ca_statedata=nacm_statedata, /* statedata */
    .ca_trans_begin=nacm_begin,             /* trans begin */
    .ca_trans_validate=nacm_validate,       /* trans validate */
    .ca_trans_complete=nacm_complete,       /* trans complete */
    .ca_trans_commit=nacm_commit,           /* trans commit */
    .ca_trans_commit_done=nacm_commit_done, /* trans commit done */
    .ca_trans_revert=nacm_revert,           /* trans revert */
    .ca_trans_end=nacm_end,                 /* trans end */
    .ca_trans_abort=nacm_abort              /* trans abort */
};

/*! Backend plugin initialization
 * @param[in]  h    Clixon handle
 * @retval     NULL Error with clicon_err set
 * @retval     api  Pointer to API struct
 */
clixon_plugin_api *
clixon_plugin_init(clicon_handle h)
{
    char  *nacm_mode;
    int    argc; /* command-line options (after --) */
    char **argv;
    int    c;
    
    clicon_debug(1, "%s backend nacm", __FUNCTION__);
    /* Get user command-line options (after --) */
    if (clicon_argv_get(h, &argc, &argv) < 0)
	goto done;
    opterr = 0;
    optind = 1;
    while ((c = getopt(argc, argv, BACKEND_NACM_OPTS)) != -1)
	switch (c) {
	case 't': /* transaction log */
	    _transaction_log = 1;
	    break;
	case 'v': /* validate fail */
	    _validate_fail_xpath = optarg;
	    break;
	}

    nacm_mode = clicon_option_str(h, "CLICON_NACM_MODE");
    if (nacm_mode==NULL || strcmp(nacm_mode, "disabled") == 0){
	clicon_log(LOG_DEBUG, "%s CLICON_NACM_MODE not enabled: example nacm module disabled", __FUNCTION__);
	/* Skip nacm module if not enabled _unless_ we use transaction tests */
	if (_transaction_log == 0) 
	    return NULL;
    }
    /* Return plugin API */
    return &api;
 done:
    return NULL;
}